The invention relates in general to gearing and in particular to a new and useful planetary gear assembly with helical and double helical gears, permitting the connection of another, faster running planetary stage to an inner central gear of the gearing. Gearings with helical and double helical gears exhibit a particularly quiet run with little noise, if the load on the planet wheels is well distributed.
A prior art planetary gearing, known from German Offenlegunsschrift No. 2618882, comprises a double helical inner central gear which is mounted on the input shaft for free axial displacement and which drives two mutually parallel sets of planet wheels which have oppositely directed helical teeth and whose planet carriers are connected to each other, one of them being connected to the output shaft through double-joint clutches, particularly double-toothed clutches.
Because the planet wheels are divided in two sets independent of each other, the torque is split by this gearing six times and a transmission of higher torques is made possible.
Another advantage of the distribution of the planet wheels to two individual sets is that antifriction bearings can be used for the gears, which results in relatively small center-to-center distances between the main component parts and thus to small overall dimensions of the gearing, so that such a gearing is very well suited, for example, for driving rolling or bending machines.
These gearings have proved suitable for relatively slow drives. With higher speeds, however, difficulties arise from additional dynamic loads caused by bigger rotating masses, which unfavorably affect the independent adjustment of the planet wheels determined by the many degrees of freedom, so that the run becomes unquiet.